The present invention relates to roofing shingles. More specifically, the present invention is concerned with a roof covering using metal roofing shingles and with a process for constructing such roof coverings.
Roof coverings made from sheet material shingles are well known. The shingles are usually made from sheet metal, notably copper, terne-coated stainless steel or aluminium, and are used to provide a long lasting roof.
Constructing metallic shingle roof coverings having water shedding joints has been attempted through either shingle overlap or folded over and interlocking edges. Simple overlapping of light gauge sheet metal shingles allows the transport of water across the overlap to the under-roof because the overlapping surfaces are not, in practice, plane, parallel, and thus, in close contact over the whole overlap area. Furthermore, the lower part of the shingles would be easily lifted by even slight winds.
That is the reason why most commercial sheet metal shingles are based on the concept of folded over edges designed to interlock with each other. However, such shingles fail to provide complete weatherproof protection.
Furthermore, folded-edge shingles have to be made from light gauge sheet metal, typically 0.020 inches thick, in order to be folded over a suitably small radius. This has an important bearing on hail resistance (proportional to the 3rd power of material thickness) and wind uplift resistance (proportional to the resistance of a fold to unfolding, which in turn is proportional to the 3rd power of material thickness). Besides this, folded-edge shingles must be made in relatively small sizes because folding and interlocking of all four sides allows practically for only one fastener per shingle; thus adequate fastening per unit surface limits the shingle size. This greatly affects manufacturing and installation costs, which depend upon shingle size.
Folded-edge shingles have another drawback when the chosen metal is aluminium. The shingles cannot be made from anodised sheet metal which cannot be folded over a small enough radius when anodised at architectural thickness (18 xcexcm and over) and post-folding anodisation is uneconomical because of the small size of the shingles. Thus, aluminium folded-over shingles are inevitably painted. This leads to the loss of the distinctive, metallic aspect and to other problems associated with volatile organic compound (VOC) emissions at the painting line, colour degradation of the roof because of organic pigment sensitivity to UV rays, and finally, obnoxious emissions when recycling either process scrap or shingles, especially if the paint contains fluorocarbons.
Prior art metallic shingles, being essentially of the folded edge design, have other shortcomings. As for aesthetics, they cannot feature rounded corners (which constitute an important element among those that can be used to design distinctive geometric roof patterns). Concerning fabrication costs, folded-edge shingles are made from blanks that have several notches and re-entrant angles, which require custom dies; the blanks must further be processed in specially designed folding machines. Special elements are needed for building the roof covering at eaves, gable edges, hips and valleys.
There is an ongoing demand for a roof covering made of metal roofing shingles, which can shed water, prevent ingress of wind-driven rain, be weather resistant, resist the assaults of wind, UV rays, snow, ice, extremes of temperature (typically from xe2x88x9240xc2x0 C. to +100xc2x0 C.) while being relatively inexpensive to manufacture, easy to construct and having aesthetic value in terms of colour, texture or geometry.
One object of the present invention is therefore to provide an improved metal roofing shingle used for building an improved roof covering.
Another object of the invention is to provide a metal roofing tile free of the above-noted disadvantages.
A further object of the invention is to provide a metal shingle having non-folded edges.
Yet, another object of the present invention is to provide a shingle that is resistant to the action of UV rays, wind, hail, temperature extremes while remaining easy and relatively inexpensive to manufacture.
Yet, a further object of the present invention is to provide a roof covering that is waterproof and has an exceptionally long life.
More specifically, in accordance with the present invention, there is provided a roofing shingle for mounting to a roof surface which comprises:
a substantially flat and generally rectangular shaped panel made of metallic sheet material, the panel having a top side and an under side and defining side edges, the top side displaying along at least two of the side edges a series of dimples defining corresponding bosses on the under side;
a series of connecting elements having one end mounted to a corresponding boss and an opposite end projecting beyond the side edges, the connecting elements allowing connection with the roof surface; and
locating means on the top and under sides for positioning the shingle with a corresponding similarly constructed shingle to define an overlapping region therebetween.
Preferably, this one end of each connecting element is pivotally mounted to the corresponding boss.
Preferably, each connecting element consists of a tab member and the other end of the connecting element displays an aperture for receiving a fastening element for connection to the roof surface.
Advantageously, when the shingle is positioned with a corresponding similarly constructed shingle, the respective under sides of the positioned shingles are substantially parallel to one another in the overlapping region.
Preferably, the locating means consist of complementary top side and under side locating elements. More preferably, one of the top side and under side locating elements is mounted near side edges devoid of connecting elements and the other of the top side and under side locating elements is mounted near side edges including connecting elements.
Preferably, the under side locating element consists of a tab member having offset first and second body portions, the first body portion being mounted to the under side and the second body portion forming a gap with the under side.
Preferably, the top side locating element consists of at least one dimple formed on the top side and a flat band partially covering the dimple, the second body portion of the tab member of a corresponding similarly constructed shingle being received in this one dimple and contacting the flat band, the flat band having a thickness equal to or less than the gap between the second body portion and the under side, and this one dimple having a depth equal to or less than the depth of the corresponding boss of each of the series of dimples.
Advantageously, the flat band has a thickness equal to or less than the thickness of the shingle.
Preferably, the second body portion of the tab member defines a resilient stopper upwardly extending therefrom and abutting the under side, the flat band defines a free edge abutting the resilient stopper of a corresponding similarly constructed shingle, and the resilient stopper is deformable so as to substantially clear the gap between the second body portion of the tab member and the under side.
Advantageously, the shingle is made of metallic material selected from the group consisting of stainless steel, terne-coated stainless steel, zinc, copper, clear-anodised aluminium and colour-anodised aluminium.
In accordance with another aspect of the present invention, there is provided a roof covering for mounting to a roof surface defining a peripheral edge, the roof covering comprising:
interconnected shingles, each shingle comprising a substantially flat and generally rectangular shaped panel made of metallic sheet material, the panel having a top side and an under side and defining side edges, the top side displaying along at least two of the side edges a series of dimples defining corresponding bosses on the underside, a series of connecting elements having one end mounted to a corresponding boss and an opposite end projecting beyond the side edges, the connecting elements allowing connection with the roof surface, and locating means on the top and under sides for positioning the shingle with a corresponding similarly constructed shingle to define an overlapping region therebetween.
Preferably, each connecting element consists of a tab member, the one end of the connecting element being pivotally riveted to the corresponding boss and the other end of the connecting element displaying an aperture for receiving a fastening element for connection to the roof surface.
Preferably, the interconnected shingles are staggered along the roof in regular arrays with their respective under sides substantially parallel to one another in the overlapping region.
Preferably, the regular arrays consist of at least four rows of overlapping shingles, the over sides and under sides of overlapping shingles are maintained in close contact in the overlapping region for any particular shingle in a given row by the interconnection of that particular shingle with a shingle in a second lower row to that given row and by the interconnection of a shingle of a first upper row to that given row with a shingle in a first lower row to that given row, and with the shingles of these first upper and first lower rows being adjacent to that particular shingle.
Preferably, the roof covering defines an outwardly projecting peripheral edge and the bosses provide a space between the under side and the outwardly projecting edge and the roof covering further comprises plates for being fitted in this space and for being connected to both the shingles and the roof and an open moulding mounted to the outwardly projecting roof peripheral edge providing ventilation of the roof covering.
Alternatively, the roof surface further includes two adjacent planes having respective inward ends that meet to form an intersection with an inward angle defining an apex line, the shingles of both planes being cut at the intersection along a line parallel to the apex line, the bosses providing a space between the under sides of the shingles and the roof surface with the plates being fitted in this space, the plates being connected to both the shingles and the roof surface.
Alternatively, the roof surface further includes two adjacent surface planes having respective uppermost ends that meet to form an outward angle, the shingles at the uppermost ends of each of the planes have respective upwardly bent portions about the outward angle, the upwardly bent portions being adjacent and substantially parallel to one another, the roof covering further comprising tube members being fastened between the adjacent bent portions, and a cap moulding capping the upwardly bent portions.
In accordance with yet another aspect of the present invention, there is provided a process for covering a roof surface using the roofing shingle of the present invention, the roof surface having a peripheral roof projecting edge overhanging a wall structure, the process comprising the steps of:
(a) mounting an elastomer membrane on the roof surface;
(b) mounting generally rectangular plates of a metallic sheet material on the projecting edge over the elastomer, the plates having a bottom edge projecting beyond the roof projecting edge;
(c) mounting a moulding made of metallic sheet material to the roof projecting edge, the moulding having a substantially flat wide portion with an upwardly curved recessed end, the wide portion is placed under the roof projecting edge and the recessed end receives the plate bottom edge therein;
(d) cutting the shingles to produce shingle-portions and mounting the shingle-portions unto the elastomer membrane and the plates with the cut edge of a the shingle-portions being fitted within the upwardly curved recess;
(e) positioning the shingles, starting with the shingle-portions, to corresponding shingles, by interconnecting the corresponding locating means, along the roof surface in a staggered manner such that the respective under sides of the positioned shingles are substantially parallel to one another in the overlapping region; and
(f) connecting the shingle connecting elements to the roof surface.
Alternatively, the roof surface further includes two adjacent surface planes having respective inward ends that meet to form an intersection with an inward angle defining an apex line, the process further comprising the steps of:
(a) mounting a metallic flashing along the intersection of the planes, extending on both sides of the apex line over such a distance sufficient for preventing rainwater from reaching the roof surface;
(b) mounting the generally rectangular plates over the metallic flashing on both sides of the apex line, the plates having a longitudinal axis and having two long sides and two short sides, the longitudinal axis is perpendicular to the apex line and the short side being closest to the apex line does not abut the apex line;
(c) mounting the moulding to the metallic flashing, the wide portion is placed under the plates and the recessed end receives the short edge closest to the apex line of the plates mounted over the flashing;
(d) cutting the shingles along a line determined by the moulding recessed end, mounting the cut shingles unto the plates with their cut edge being fitted within the upwardly curved recess of the moulding.
Alternatively, the roof surface further includes two adjacent surface planes having respective uppermost ends that meet to form an outward angle, the process further comprising the steps of:
(a) upwardly bending the shingles at the uppermost ends, such that the uppermost end shingles of the two surface planes form two substantially parallel adjacent bent portions about the outward angle;
(b) placing a tube member between the adjacent bent portions, the tube member being snugly fitted therebetween and having opposite sides, each opposite sides being connected to a respective bent portion to from a tube-shingle assembly; and
(c) capping the tube-shingle assembly with a cap moulding.
In accordance with still yet another aspect of the present invention, there is provided a metal roofing shingle for mounting to a roof surface, the shingle having a substantially flat and generally rectangular configuration and comprising:
spacing means for upwardly spacing the shingle from the roof surface;
connecting means for mounting the shingle to the roof surface, the connecting means having means so as to be adaptable to thermal expansion and contraction of the shingle; and
locating means for positioning the shingle with a corresponding similarly constructed shingle, the locating means having means so as to be adaptable to thermal expansion and contraction of the shingle.
Other objects, advantages and features of the present invention will become more apparent upon reading of the following non restrictive description of preferred embodiments thereof, given by way of example only, with reference to the accompanying drawings.